Phippsburg Replaces Fish Channel with Rock-Pool Solution

MAINE — Phippsburg, Maine, replaced its fish channel with a rock-pool solution in 2025. The new structure aims to restore alewife migration after the previous channel, built in the 1980s, sat more than 2 feet above the water at low tide, blocking migration for more than half of every day.

Dams created barriers to alewife migration in Maine rivers beginning in the 1700s. By the 1840s, dams downstream of Benton had reduced the town's alewife harvest. Maine progressively placed more limits on commercial alewife harvests from the 1960s through the 1990s. In 1994, Maine's town harvests caught 150,000 pounds of alewives, a decrease from a peak of more than 3 million pounds. In 2012, the Atlantic States Marine Fisheries Commission instituted a moratorium on all commercial alewife fishing on the Atlantic coast. Lobster boats in Maine use alewives as bait.

The rock-pool solution in Phippsburg is similar to a fishway in Penobscot, which consists of a series of rocky pools. Troy Wallace, alewife committee chair in Phippsburg, has served on the committee for 14 years. To prepare for fish-access projects, the Maine Department of Marine Resources must stock alewives in the target pond or lake about five years in advance.

Dam removals and fish channel construction have reopened sections of Maine's rivers to alewife migration since the 1990s. The effort to remove two dams on Maine's Penobscot River started in 1999 and was completed in 2016. In Benton, engineers built a fish lift on the hydroelectric dam in 2006. This lift uses a large bucket that dips into the downstream side of the river every five minutes to transport alewives over the dam.

Alewives live mostly in the Atlantic Ocean from Newfoundland to South Carolina. In early summer, adult alewives migrate as far as 100 miles inland to spawn in ponds and lakes. Unlike some other fish, alewives do not die after spawning. They act as a biological conveyor belt of nutrients between the ocean and inland waters, serving as a food source for seals, otters, bald eagles, ospreys, pollock, and trout.